1. Field of the Invention
One disclosed aspect of the embodiments relates to an image pickup apparatus. In particular, an embodiment relates to a configuration including signal holding units in a pixel.
2. Description of the Related Art
Up to now, an image pickup apparatus of a pixel amplification type provided with an amplification element for each pixel is proposed. The respective pixels of the image pickup apparatus of the pixel amplification type may hold a signal in a photoelectric conversion unit and an input node of the amplification element. In the above-described image pickup apparatus of the pixel amplification type, a global electronic shutter technology is developed with which exposure periods may be set identical over an entire image pickup surface. Plural configurations for realizing the global electronic shutter are proposed. In particular, a configuration of including, in addition to the photoelectric conversion unit and the input node of the amplification element, a signal holding unit on an electric path between the photoelectric conversion unit and the input node of the amplification element is proposed. Furthermore, a configuration of including plural signal holding units between the photoelectric conversion unit and the input node of the amplification element is also proposed (Japanese Patent Laid-Open No. 2009-296674 and Japanese Patent Laid-Open No. 2011-217315.
In a case where the signal holding unit is arranged in the pixel in addition to the photoelectric conversion unit and the input node of the amplification element, a light-shielding member is generally arranged in this signal holding unit so that light incidence is avoided while the signal is held (for example, paragraph 0065 of Japanese Patent Laid-Open No. 2011-217315). However, the area of the light-shielding member is increased, and in accordance with this, the exclusive area for the signal holding unit in the pixel is increased. Along with this, a sensitivity of the photoelectric conversion unit is decreased. The above-described phenomenon is particularly prominent in a case where the plural signal holding units are provided in the pixel.